John Sayles almost always makes movies about fascinating, neglected subjects and he almost always fails to do them justice.

He's been at it for almost 30 years, and his skills have pretty much remained the same: Good with dialogue, so-so with the camera. In addition to writing and directing his films, he also edits them, or to be more precise, he lets them run on too long.

His new film, "Honeydripper," is medium-grade Sayles. (I'd place "Return of the Secaucus Seven," "Matewan," and "Lone Star" at the top.) Set in 1950 in rural Alabama during cotton harvest season, it's a poky fable that takes its sweet time getting to nowhere in particular.

Piano player Tyrone "Pine Top" Purvis (Danny Glover), who owns the Honeydripper Lounge, is desperately fending off debt until he has a brainstorm: Book local celebrity Guitar Sam, rake in the proceeds on Saturday night, and keep the landlord at bay. When Guitar Sam fails to show, a young itinerant bluesman, Sonny Blake (real bluesman Gary Clark Jr.), is hired as his impersonator.

With his electric guitar and electric personality, Sonny is intended to be a fictional equivalent of the young Chuck Berry. He's the avatar of rock 'n' roll. It might have been better if Sayles had just tried to make the Chuck Berry story instead. His depiction of rural, 1950s black America is reasonably well done, especially considering his low budget, and yet almost nothing in the film, apart from the music, seems authentic.

The characters speak a corn-pone argot that's too self-consciously literary, and many of the scenes, such as the ones between Tyrone and the white, racist sheriff (Stacy Keach), are familiar.

There's even a blind bluesman (Keb' Mo') who acts as a kind of Greek chorus. What would movies like these be without blind bluesmen?

Still, Sayles has great affection for his characters, and the actors who play them are a pleasant bunch.